Increase the Toughness of Material of Construction Using Heat Treatment

Abstract

The objective of this research is study on the fatigue strength and fracture behavior of DIN 34CrNiMo6 steel. The specimens were subjected to repeated torsion loading. The type of this steel generally used for turbine rotor, crankshaft, and gear. These components operate in elevation temperature and subjected by fatigue load. The test of fatigue strength were carried out under repeated torsion with variation of angle 10, 20, 30, and 40. The test temperature are also varied. on 5000C and 7000C and than compared to without heating one. The fracture surface were analyzed using scanning electron microscope (SEM) in order to identified the influence of temperature and variation of angles. The results of studies show that either the fatigue strength or fracture surface behavior are significant different. The value of fatigue strength under cyclic torsion which is heated on 7000C is higher than 5000C and original ones. Characteristic of surface fracture using scanning electron microscope showed that the increasing of temperature also change pattern of fracture surface significantly. On 7000C heating the fracture surface is smoother than others. On the specimen without heating plastic deformation area of fracture surface is clearer than others.